/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.handler.codec;

import io.netty.util.Signal;

public class DecoderResult
{

    protected static final Signal SIGNAL_UNFINISHED = Signal
            .valueOf(DecoderResult.class, "UNFINISHED");

    protected static final Signal SIGNAL_SUCCESS = Signal
            .valueOf(DecoderResult.class, "SUCCESS");

    public static final DecoderResult UNFINISHED = new DecoderResult(
            SIGNAL_UNFINISHED);

    public static final DecoderResult SUCCESS = new DecoderResult(
            SIGNAL_SUCCESS);

    public static DecoderResult failure(Throwable cause)
    {
        if (cause == null)
        {
            throw new NullPointerException("cause");
        }
        return new DecoderResult(cause);
    }

    private final Throwable cause;

    protected DecoderResult(Throwable cause)
    {
        if (cause == null)
        {
            throw new NullPointerException("cause");
        }
        this.cause = cause;
    }

    public boolean isFinished()
    {
        return cause != SIGNAL_UNFINISHED;
    }

    public boolean isSuccess()
    {
        return cause == SIGNAL_SUCCESS;
    }

    public boolean isFailure()
    {
        return cause != SIGNAL_SUCCESS && cause != SIGNAL_UNFINISHED;
    }

    public Throwable cause()
    {
        if (isFailure())
        {
            return cause;
        }
        else
        {
            return null;
        }
    }

    @Override
    public String toString()
    {
        if (isFinished())
        {
            if (isSuccess())
            {
                return "success";
            }

            String cause = cause().toString();
            return new StringBuilder(cause.length() + 17).append("failure(")
                    .append(cause).append(')').toString();
        }
        else
        {
            return "unfinished";
        }
    }
}
